Short circuit detection device

Abstract

The invention relates to a short circuit detection device in a direct current circuit. The short circuit detection device comprises a voltage source; a bus bar comprising at least two conductive elements, each conductive element coupled to any one of the terminals of the voltage source; a first thyristor and a second thyristor coupled to the voltage source and coupled to the bus; and at least one capacitive element forming a memory capacitor, the electrodes of which are each coupled to any one of the conductive elements of the bus bar, the at least one control circuit is configured to control biasing and operating modes of the first and second thyristors such that a short circuit detection phase is implemented prior to pre-charging of the storage capacitor.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to French patent application No. 2306003, filed on June 13, 2023, entitled “Dispositif de detection decourt-circuit”, which is hereby incorporated by reference to the maximum extent permitted by law. Technical Field

[0003] The present disclosure generally relates to short circuit detection devices. Background Art

[0004] In a DC circuit, such as in an electric vehicle, the battery of the vehicle is coupled to a bus comprising two conductive elements, each of which is coupled to one terminal of the battery, respectively. The capacitive element of the circuit coupled to the bus can be considered a bulk capacitor or storage capacitor, which is coupled in parallel with the battery through a relay capable of connecting / disconnecting the battery to / from the bus and the conductive element of the bus.

[0005] When the relay is closed to connect the busbar to the battery, a strong inrush current flows between the battery and the storage capacitor. In order to prevent this inrush current, the storage capacitor is usually precharged using a precharge current before closing the relay. To this end, a precharge circuit including a precharge resistor and a switch can be coupled in parallel with one of the relays. The precharge of the storage capacitor is achieved by closing the switch and keeping the relay coupled in parallel with the precharge circuit disconnected while closing the other relays. The precharge phase is performed for a duration that is long enough to obtain the desired precharge voltage at the terminals of the storage capacitor.

[0006] If there is a short circuit in the DC circuit, a strong current flows through the switch and may damage other components coupled to the bus. When the switch of the pre-charge circuit is a thyristor, turning off the thyristor to stop this short circuit current involves additional circuitry.

[0007] When the switch of the pre-charge circuit is a relay, the relay can be simply opened to stop the short-circuit current. However, given the delay required to open the relay, the short-circuit current may have time to damage other components coupled to the bus. In addition, the opening delay of the relay increases over time. Summary of the invention

[0008] A solution is needed to deal with the problems of existing solutions.

[0009] A specific embodiment provides a solution to at least some of these problems and proposes a short circuit detection device for detecting a short circuit in a DC circuit, the short circuit detection device comprising: at least one voltage source; a bus bar comprising at least two conductive elements, each conductive element coupled to any one of the terminals of the voltage source; a first thyristor and a second thyristor coupled to the voltage source and to the bus bar; and at least one capacitive element forming a storage capacitor, each electrode of which is coupled to any one of the conductive elements of the bus bar, wherein the short circuit detection device comprises at least one control circuit, the at least one control circuit being configured to control the first thyristor The invention relates to a method for controlling a short circuit in a storage capacitor and a method for controlling a first thyristor and a second thyristor, wherein the first thyristor and the second thyristor are biased and operated in a mode such that: during a detection phase of a short circuit, the first thyristor is placed in an off state and the second thyristor is reverse biased and conducts a non-zero reverse current for charging a storage capacitor, after which the voltage at the terminals of the storage capacitor is determined; then, if the determined voltage at the terminals of the storage capacitor is less than or equal to a short circuit threshold, the first thyristor and the second thyristor are turned off, or if the determined voltage at the terminals of the storage capacitor is higher than the short circuit threshold, the storage capacitor is precharged by turning off the second thyristor and by turning on the first thyristor.

[0010] According to an embodiment, the short-circuit threshold is equal to zero.

[0011] According to an embodiment: the voltage source is a DC voltage source including at least one battery; the DC circuit includes at least a first switch and at least a second switch, wherein the at least first switch couples the positive terminal of the battery to the first of the two conductive elements of the bus, and the at least second switch couples the negative terminal of the battery to the second of the two conductive elements of the bus; at least one of the first switch and the second switch is a relay; the DC circuit includes a discharge circuit of the storage capacitor, wherein the discharge circuit includes at least a third switch coupled in series with at least one discharge resistor, and the discharge circuit is coupled in parallel with the storage capacitor; the first thyristor is part of a precharge circuit, and the precharge circuit also includes a precharge resistor coupled in series with the first thyristor, wherein the precharge circuit is coupled in parallel with one of the first switch and the second switch, and the cathode of the first thyristor is coupled to the negative terminal of the battery, or the anode of the first thyristor is coupled to the positive terminal of the battery; and the second thyristor is coupled in parallel with one of the first switch and the second switch, and the anode of the second thyristor is coupled to the negative terminal of the battery, or the cathode of the second thyristor is coupled to the positive terminal of the battery.

[0012] According to an embodiment, the control circuit is configured to apply the control signal to the gates of the first thyristor and the second thyristor, or the short circuit detection device further includes a Zener diode and an RC circuit, the anode of the Zener diode is coupled to the gate of the first thyristor, the cathode of the Zener diode is coupled to the anode of the second thyristor and to the first terminal of the RC circuit, and the second terminal of the RC circuit is coupled to the cathode of the first thyristor.

[0013] According to one embodiment, the control circuit is configured to: before the short circuit detection phase, close the first switch; then perform an initial measurement of the voltage at the terminals of the storage capacitor; thereafter start the short circuit detection phase if the initial voltage measurement at the terminals of the storage capacitor is lower than or equal to the short circuit threshold, or directly pre-charge the storage capacitor if the voltage initially measured at the terminals of the storage capacitor is higher than the short circuit threshold.

[0014] According to an embodiment, if the anode of the second thyristor is coupled to the negative terminal of the battery, the control circuit is configured to control the first switch such that it is conducting during the short circuit detection phase and during pre-charging of the storage capacitor.

[0015] According to an embodiment, the control circuit is configured such that after pre-charging of the storage capacitor, the first switch and the second switch are turned on, and the first thyristor and the second thyristor are turned off.

[0016] According to an embodiment, the third switch is a third thyristor, and the control circuit is configured to apply the control signal to a gate of the third thyristor.

[0017] According to an embodiment, during a battery-bus disconnection phase performed after pre-charging of the storage capacitor, the control circuit is configured to turn on the third switch after the first switch and the second switch are turned off.

[0018] According to an embodiment, during the measurement of the voltage at the terminals of the storage capacitor carried out during the short circuit detection phase, the control circuit is configured to switch off the second thyristor.

[0019] According to another embodiment, a vehicle battery control system is provided, which includes at least one short circuit detection device as described above.

[0020] According to another embodiment, a power converter is provided, which includes at least one short-circuit detection device as described above.

[0021] According to an embodiment, the first thyristor and the second thyristor are part of a commutation cell of a power converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above-mentioned features and advantages and other features and advantages will be described in detail in the following description of specific embodiments given by way of illustration and not limitation, with reference to the accompanying drawings, in which:

[0023] Figure 1 schematically illustrates a first exemplary embodiment of a short circuit detection device according to certain embodiments;

[0024] Figure 2 and Figure 3 shows a timing diagram of signals of a short circuit detection device according to a first exemplary embodiment;

[0025] Figure 4 schematically illustrates a second exemplary embodiment of a short circuit detection device according to certain embodiments;

[0026] Figure 5 shows a timing diagram of signals of a short circuit detection device according to a second embodiment;

[0027] Figure 6 An example embodiment of a power converter including a short circuit detection device according to certain embodiments is schematically represented. DETAILED DESCRIPTION

[0028] In the various drawings, the same features are indicated by the same reference numerals. In particular, common structural and / or functional features in various embodiments may have the same reference numerals and may be arranged with the same structure, size and material properties.

[0029] For the sake of clarity, the operation and elements of the embodiments described herein have been illustrated and described in detail to facilitate understanding. In particular, the details of the various elements (power supply, busbar, thyristor, control circuit, etc.) of the short circuit detection device are not described in detail. Those skilled in the art will be able to implement these elements based on the functional description provided herein.

[0030] Unless otherwise specified, when two elements are referred to as being connected together, this means a direct connection without any intermediate elements except conductors, and when two elements are referred to as being coupled together, this means the two elements may be connected or they may be coupled via one or more other elements.

[0031] Unless otherwise specified, the expressions "around", "approximately", "substantially" and "about" mean within 10%, and preferably within 5%.

[0032] also, Figure 2 , Figure 3 and Figure 5The timing diagram signals are schematically represented and are not represented to the same scale with respect to the amplitude and duration of the individual parts of these signals. Therefore, signals symbolically shown as rectangular signals in these figures may correspond to pulse signals or signals of other shapes.

[0033] Combine the following Figure 1 A first example of the short-circuit detection device 100 is described.

[0034] In this first embodiment, the apparatus 100 may detect a short circuit in a DC circuit (eg, part of the system 1000 ) to command a vehicle (such as an electric vehicle) battery before the battery is coupled to the vehicle's DC current bus.

[0035] The DC circuit comprises at least one voltage source 102, which in this first example is a DC voltage source comprising at least one battery and outputting a DC current. For example, the voltage at the terminals of the battery is about 400V or 800V.

[0036] The DC circuit also includes a busbar including at least two conductive elements 104, 106, each conductive element being coupled to any one of the terminals of the voltage source 102. In the first embodiment described, the first conductive element 104 is coupled to the positive terminal of the voltage source 102 via a first switch 108, and the second conductive element 106 is coupled to the negative terminal of the voltage source 102 via a second switch 110.

[0037] In this first embodiment, at least one of the first and second switches 108, 110 is a relay, so that the voltage source 102 can be physically disconnected from the busbar without any leakage. Figure 1 In the example of , both switches 108, 110 are relays. As a variant, one of the two switches 108, 110 may not be a relay and may be, for example, a semiconductor system such as a power transistor or any other electronic component suitable for forming such a switch.

[0038] The apparatus 100 further includes first and second thyristors 112 , 114 coupled to the voltage source 102 and to the bus.

[0039] In the first described embodiment, the first thyristor 112 is part of a precharge circuit that also includes a precharge resistor 116 coupled in series to the first thyristor 112. The precharge circuit is coupled in parallel with the first and second switches 108, 110 (in Figure 1 In the example of , connected in parallel with the second switch 110). In addition, Figure 1In the example of , the cathode of the first thyristor 112 is coupled to the negative terminal of the voltage source 102 . As a variant, the pre-charging circuit may be coupled in parallel with the first switch 108 ; in this case, the anode of the first thyristor 112 is coupled to the positive terminal of the voltage source 102 .

[0040] exist Figure 1 In the example of , the second thyristor 114 constitutes a short circuit detection circuit, which is coupled in parallel with one of the first and second switches 108 and 110. Figure 1 In the example of , the second thyristor 114 is coupled in parallel with the second switch 110. Furthermore, the anode of the second thyristor 114 is coupled to the negative terminal of the voltage source 102. As a variant, the second thyristor 114 may be coupled in parallel with the first switch 108; in this case, the cathode of the second thyristor 114 is coupled to the positive terminal of the voltage source 102.

[0041] In this particular embodiment, the DC circuit includes one or more capacitive elements that together form a storage capacitor 118 (also referred to as a bulk capacitor), with each electrode coupled to either of the conductive elements 104, 106 of the busbar.

[0042] In this embodiment, the device 100 further includes a discharge circuit for the storage capacitor 118, the discharge circuit including at least one third switch 120 connected in series with at least one discharge resistor 122. The discharge circuit is coupled in parallel with the storage capacitor 118. Figure 1 In the example of FIG. 4 , the third switch 120 is a third thyristor.

[0043] The device 100 further comprises at least one control circuit 124, comprising, for example, at least one microcontroller, which is configured to control the biasing of the first, second and third thyristors 112, 114, 120 (in particular due to commands to open and close each of the first and second switches 108, 110) and the operating modes of the first, second and third thyristors 112, 114 and 120. In a first example, the operating modes of the first, second and third thyristors 112, 114, 120 are controlled due to control signals applied to the gates of the thyristors 112, 114, 120 from the control circuit 124. Figure 1 In the embodiment, the control signal "CTRL1" is applied to the gate of the first thyristor 112, the control signal "CTRL2" is applied to the gate of the second thyristor 114, and the control signal "CTRL3" is applied to the gate of the third thyristor 120. Figure 1 In FIG. 1 , electrical connections between the switches 108 , 110 and the control circuit 124 and between the thyristors 112 , 114 , 120 and the control circuit 124 are not shown.

[0044] In a particularly described embodiment, the device 100 further includes a voltage divider bridge coupled in parallel with the storage capacitor 118 to the conductive elements 104, 106 of the busbar. Figure 1 In the example of , the voltage divider bridge comprises two resistors 126, 128. If the values ​​of the resistors 126, 128 are known, the voltage measured at the terminals of either resistor 126, 128 makes it possible to determine the value of the voltage at the terminals of the storage capacitor 118 (which represents the voltage at the DC current bus).

[0045] In addition, Figure 1 In the example of FIG. 1 , the gates of the first and second thyristors 112 , 114 are coupled to resistors through which the control signal is applied.

[0046] Although not shown, there may be fused terminals between the voltage source 102 and the busbar. Additionally, other components or circuits such as power converters may also be coupled to the busbar, and these components are not shown in the figures.

[0047] The following describes the above combination Figure 1 An example of a process implemented by apparatus 100 is described. Figure 2 An example of control signals and measurements obtained by this process is shown, matching the process of connecting the voltage source 102 to the bus with a previous check for the presence of a short circuit on the DC circuit. Figure 3 The same signal is shown in case a short circuit is detected on the circuit, which means that the holding voltage source 102 is disconnected from the busbar.

[0048] exist Figure 2 and Figure 3 , a high value of the signals "Relay 1" and "Relay 2" represents a command to close the switches 108, 110, while a low value of these signals represents a command to open these switches 108, 110. Furthermore, a high value of the signals "CTRL1" and "CTRL2" represents a command to turn on the thyristors 112, 114, while a low value of these signals represents a command to turn off these thyristors 112, 114.

[0049] In the described embodiment, in an initial state of the process, the first and second switches 108 , 110 are open, and the first, second, and third thyristors 112 , 114 , 120 are turned off.

[0050] In the first stage of the process (corresponding to Figure 2 and Figure 3 During the duration between time t0 and time t1), the control circuit 124 sends a first control signal to the first switch 108 (during Figure 2and Figure 3 Referred to as "Relay 1", the first control signal commands the closing of the switch.

[0051] In this example, the voltage at the terminals of the storage capacitor 118 is calculated during this first phase (e.g., calculated from the measured value of the voltage at the terminals of one of the resistors 126, 128) and compared with a short-circuit threshold. For example, the short-circuit threshold is equal to 0 and defines a limit value, so that if during this first phase, the voltage at the terminals of the storage capacitor 118 is higher than the threshold, it indicates that there is no short circuit in the DC circuit. The method can then directly perform the pre-charging phase of the body capacitor 118 described later.

[0052] If during the first phase of the method the voltage at the terminals of the bulk capacitor 118 remains below or equal to the threshold, this indicates that the bulk capacitor 118 is not charged or there is a short circuit in the DC circuit. Figure 2 and Figure 3 In the example of , the voltage at the terminals of the storage capacitor 118 (referred to as "VC1") remains zero even after closing the first switch 108, which indicates that there may be a short circuit in the DC circuit. In this case, a short circuit detection phase is implemented.

[0053] Short circuit detection circuit Figure 2 and Figure 3 The execution is performed between the times t1 and t2 shown. During this phase, the first thyristor 112 is turned off (at Figure 2 and Figure 3 1-1 , the control signal "CTRL2" sent by the control circuit 124 to the gate of the first thyristor 112 remains zero), and the reverse biased second thyristor 114 conducts a non-zero reverse current during the duration t2-t1. The conduction of the reverse current by the second thyristor 114 is obtained due to the reverse bias and the current applied by the control circuit 124 to the gate of the second thyristor 114 that produces this conduction. The value of the reverse current obtained is proportional to the value of the current applied to the gate of the second thyristor 114, and the value of the proportionality coefficient β between these two currents depends on the characteristics of the second thyristor 114. For example, the current applied to the gate of the second thyristor 114 can be about 16 mA, or more generally between 10 mA and 16 mA, so as to obtain a reverse conduction current between 6 mA and 10 mA.

[0054] exist Figure 2 In the embodiment of the present invention, this reverse conduction current flowing through the second thyristor 114 generates a slow discharge of the storage capacitor 118, and thus a small increase in the voltage at the terminals of the storage capacitor 118. For example, this small increase in the voltage at the terminals may be equal to 10V, or more generally between 1% and 5% of the battery voltage. Figure 3 In the embodiment of FIG. 1 , because of the short circuit in the DC circuit, this small reverse conduction current flowing through the second thyristor 114 does not charge the storage capacitor 118. For example, the voltage is determined from the measured value at the voltage divider bridge and then compared with the short circuit threshold.

[0055] The duration t of the short-circuit detection phase is calculated according to the following relationship:

[0056] Mathematical formula 1

[0057]

[0058] Where C is the value of the storage capacitor 118, ΔV is the increase in voltage at the terminals of the storage capacitor 118, and I R is the reverse conduction current that charges the storage capacitor 118. For example, for the current I R is equal to 16 mA, the capacitor C is equal to 0.67 mF and the voltage increment ΔV is equal to 10 V, the duration t is equal to 425 ms.

[0059] If the determined voltage is equal to or below the short-circuit threshold, for example equal to 0 in the example described here, the first and second thyristors 112, 114 are switched off and the process ends, since this indicates that a short circuit has been detected in the DC circuit. In this case, the voltage source 102 is not connected to the busbar. This situation corresponds to Figure 3 A situation is shown in FIG. 1 , where the voltage VC1 is zero at time t2 . In case of a short circuit, the first switch 108 is open (the signal “Relay 1” changes to a lower value starting from t2 ).

[0060] If the determined voltage is above the short-circuit threshold, such as Figure 2 As shown in the timing diagram of , the pre-charging phase of the body capacitor 118 is performed. The second thyristor 114 is turned off (the signal "CTRL2" switches to a lower value), and the forward biased first thyristor 112 is turned on by applying a higher value "CTRL1" signal to the gate of the first thyristor 112 by the control circuit 124. Then, since the current through the storage capacitor 118 is only limited by the pre-charging resistor 116 and no longer by the reverse bias of the second thyristor 114, the storage capacitor 118 is charged faster than in the short-circuit detection phase.

[0061] Figure 2The instant t3 in corresponds to the instant when the desired pre-charge voltage value is reached at the terminals of the storage capacitor 118. For example, the desired value of the pre-charge voltage may be between 80% and 90% of the voltage at the terminals of the voltage source 102. The control signal applied to the gate of the first thyristor 112 is thus withdrawn (the "CTRL1" signal switches to a low value), and the second switching element 110 is closed. The first thyristor 112 is then switched to the off state, since the current passes through the second switching element 110 instead of the first thyristor 112, which connects the voltage source 102 to the busbar (the first switch 108 remains closed after the instant t3).

[0062] Thus, by controlling the various elements of the device 100 as described above, monitoring the current through the bus before precharging of the storage capacitor 118 begins prevents the precharging from occurring if a short circuit on the bus is detected. In addition, the integrity of any fuses between the voltage source 102 and the bus is preserved.

[0063] When the voltage source 102 is disconnected from the busbar, for example when stopping the vehicle, after (or even during) pre-charging of the storage capacitor 118, the control circuit 124 turns on the third thyristor 120 and turns off the first and second switches 108, 110. The storage capacitor 118 is then discharged through the discharge resistor 122, which limits the value of the current in this discharge phase.

[0064] Combine the following Figure 4 A second exemplary embodiment of the short circuit detection device 100 is described.

[0065] The apparatus 100 according to the second exemplary embodiment comprises the apparatus according to the above Figure 1 All elements of the device 100 of the first exemplary embodiment are described.

[0066] In addition to these elements, the device 100 according to this second exemplary embodiment further comprises a Zener diode 130, an anode of which is coupled to the gate of the first thyristor 112. A cathode of the Zener diode 130 is coupled to a terminal of an RC circuit (comprising a resistor 132 and a capacitor 134), and to an anode of the second thyristor 114. A second terminal of the RC circuit is coupled to a cathode of the first thyristor 112.

[0067] Figure 5 A timing diagram of signals of the device 100 according to the second example embodiment is shown when a short circuit is detected before the voltage source 102 is connected to the busbar.

[0068] In this timing diagram, the various signals shown are combined with the previous Figure 2 and Figure 3Those described match, except for the signal “VC2” corresponding to the voltage at the terminals of Zener diode 130 .

[0069] Between times 0 and t1 (which represents the period during which the voltage at the terminals of the storage capacitor 118 is initially measured), the voltage at the terminals of the Zener diode 130 remains zero. Figure 2 and Figure 3 Those described. As previously described, if the voltage at the terminals of the storage capacitor 118 determined during this first phase is above the short-circuit threshold, this indicates that there is no short circuit in the DC circuit. The method can then implement a pre-charging phase of the storage capacitor 118. If the voltage remains below or equal to this threshold, this indicates that the storage capacitor 118 is not charged or that there is a short circuit in the DC circuit. In this case, the method does not implement a pre-charging phase and reports that a potential short circuit has been detected.

[0070] Between the instants t1 and t2 (short-circuit detection phase), the second thyristor 114 is reverse biased and conducts a weak reverse current that slowly charges the storage capacitor 118. This reverse current also charges the capacitor 134, thereby increasing the voltage VC2 at the terminals of the Zener diode 130. Then, the voltage at the terminals of the storage capacitor 118 is determined, and if this voltage is above the short-circuit threshold, the pre-charging phase of the storage capacitor 118 begins. If it is equal to or below the short-circuit threshold, the second thyristor 114 is turned off and the switches 108, 110 are opened.

[0071] exist Figure 5 In the example of FIG. 1 , at the instant t2, the precharging phase of the storage capacitor 118 begins. The first thyristor 112 is turned on due to the control signal, which is automatically applied to the gate of the first thyristor 112 by the Zener diode 130 due to the increase in the voltage at the terminals of the Zener diode 130 during the short-circuit detection phase. The instant t3 symbolically shows that the second thyristor 114 switches to the off state. If a short circuit has been detected in the circuit, the control signal applied to the gate of the second thyristor 114 is withdrawn before the voltage at the terminals of the capacitor 134 reaches the value of the threshold voltage of the Zener diode 130, so as to avoid the start-up and thus the conduction of the first thyristor 112.

[0072] Figure 5 The instant t4 in corresponds to the instant when the desired pre-charge voltage value is reached at the terminals of the storage capacitor 118. Then, the second switch 110 is closed, which connects the voltage source 102 to the busbar (the first switch 108 remains closed after the instant t4).

[0073] Similar to the first embodiment described above, by controlling the various elements of the device 100 according to the second embodiment, the current through the bus is monitored before the automatically triggered pre-charging of the storage capacitor 118 begins, and such pre-charging is prevented from being achieved if a short circuit is detected on the bus.

[0074] As in the first embodiment, when the voltage source 112 should be disconnected from the bus, the control circuit 124 turns off the first and second switching elements 108, 110 and then turns on the third thyristor 120. Thereafter, the storage capacitor 118 is discharged through the discharge resistor 122.

[0075] The different variants as described above in conjunction with the first example embodiment of the apparatus 100 also apply to the second example embodiment of the apparatus 100 .

[0076] As described above in the context of a system 1000 for controlling a vehicle battery, the short circuit detection device 100 relies on the use of a reverse biased thyristor which conducts a non-zero reverse current during a short circuit detection phase of detecting a short circuit to increase the voltage at the terminals of a storage capacitor coupled to the bus and, if a short circuit has not yet been detected, to check whether a short circuit exists before triggering pre-charging of the storage capacitor.

[0077] This device 100 can also be used inside the power converter 2000. Figure 6 An example of such a converter 2000 is described.

[0078] exist Figure 6 In the example of , the converter 2000 is a bidirectional totem-pole PFC («Power Factor Corrector») which allows converting or adapting an AC voltage into a DC voltage or, conversely, converting or adapting a DC voltage into an AC voltage.

[0079] In this embodiment, the voltage source 102 is an AC voltage source, one terminal of which is coupled to the inductive element 202. In addition, the converter 2000 includes a commutation unit made of two transistors 204, 206 and four thyristors 208, 210, 212 and 214. The commutation arm of the converter 2000 is coupled in parallel with the storage capacitor 118. Figure 6 The control circuit 124 that controls the commutation of the transistors and thyristors of the converter 2000 is not shown.

[0080] When the converter 2000 converts or adapts an AC voltage to a DC voltage, the elements used for commutation are the transistors 204, 206 and the two thyristors 208, 210. When the converter 2000 converts or adapts a DC voltage to an AC voltage, the elements used for commutation are the transistors 204, 206 and the two other thyristors 212, 214. Therefore, in both cases, the two thyristors not used for commutation are controlled by the control circuit 124 similarly to the first and second thyristors 112, 114 as previously described for the system 1000 for controlling a battery of a vehicle, which means that reverse conduction for charging the storage capacitor 118 is achieved by using a reverse biased thyristor, and then, if the voltage at the terminals of the storage capacitor 118 is above the short-circuit threshold, the other forward biased thyristors are used to achieve precharging of the storage capacitor 118.

[0081] The device 100 may be used for other types of converters, for example unidirectional converters, such as converters integrating a hybrid bridge coupled to a «Boost» circuit.

[0082] Various embodiments and variations have been described. Those skilled in the art will appreciate that certain features of these embodiments may be combined, and those skilled in the art will readily conceive of other variations.

[0083] Finally, actual implementation of the embodiments and variants described herein is within the capabilities of those skilled in the art based on the functional description provided above.

[0084] A short circuit detection device (100) can be summarized as being used for detecting a short circuit in a DC circuit, comprising: at least one voltage source (102); a busbar comprising at least two conductive elements (104, 106), each conductive element coupled to any one of the terminals of the voltage source (102); a first thyristor and a second thyristor (112, 114), coupled to the voltage source (102) and to the busbar; and at least one capacitive element forming a storage capacitor (118), electrodes of the storage capacitor each coupled to any one of the conductive elements (104, 106) of the busbar, wherein the short circuit detection device (100) comprises at least one control circuit (124), the control circuit being configured to control the first thyristor and the second thyristor (112, 114) to detect a short circuit in a DC circuit. 2, 114) and an operating mode such that: during a detection phase of a short circuit, the first thyristor (112) is placed in an off state and the second thyristor (114) is reverse biased and conducts a non-zero reverse current for charging a storage capacitor (118), after which the voltage at the terminals of the storage capacitor (118) is determined; then, if the determined voltage at the terminals of the storage capacitor (118) is less than or equal to a short circuit threshold, the first thyristor (112, 114) is turned off, or if the determined voltage at the terminals of the storage capacitor (118) is higher than the short circuit threshold, the storage capacitor (118) is precharged by turning off the second thyristor (114) and by turning on the first thyristor (112).

[0085] The short circuit threshold may be equal to zero.

[0086] The voltage source (102) may be a DC voltage source including at least one battery; the DC circuit may include at least a first switch (108) and at least a second switch (110), wherein the at least first switch (108) couples the positive terminal of the battery to the first conductive element (104) of the two conductive elements of the bus, and the at least second switch (110) couples the negative terminal of the battery to the second conductive element (106) of the two conductive elements of the bus; at least one of the first switch and the second switch (108, 110) may be a relay; the DC circuit may include a discharge circuit of the storage capacitor (118), the discharge circuit including at least a third switch (120) coupled in series with at least one discharge resistor (112), the discharge circuit The first thyristor (112) is coupled in parallel with the storage capacitor (118); the first thyristor (112) may be part of a precharge circuit, the precharge circuit also including a precharge resistor (116) coupled in series with the first thyristor (112), wherein the precharge circuit is coupled in parallel with one of the first switch and the second switch (108, 110) and enables the cathode of the first thyristor (112) to be coupled to the negative terminal of the battery, or the anode of the first thyristor (112) to be coupled to the positive terminal of the battery; the second thyristor (114) may be coupled in parallel with one of the first switch and the second switch (108, 110) and enables the anode of the second thyristor (114) to be coupled to the negative terminal of the battery, or the cathode of the second thyristor (114) to be coupled to the positive terminal of the battery.

[0087] The control circuit (124) may be configured to apply a control signal to the gates of the first thyristor and the second thyristor (112, 114), or the short circuit detection device (100) may further include a Zener diode (130) and an RC circuit (132, 134), the anode of the Zener diode (130) being coupled to the gate of the first thyristor (112), the cathode of the Zener diode (130) being coupled to the anode of the second thyristor (114) and to a first terminal of the RC circuit (132, 134), and the second terminal of the RC circuit (132, 134) being coupled to the cathode of the first thyristor (112).

[0088] The control circuit (124) can be configured to: before the short circuit detection phase, close the first switch (108) and then perform an initial measurement of the voltage at the terminals of the storage capacitor (118); thereafter, if the initial voltage measurement value at the terminals of the storage capacitor (118) is lower than or equal to the short circuit threshold, start the short circuit detection phase, or if the voltage initially measured at the terminals of the storage capacitor (118) is higher than the short circuit threshold, directly pre-charge the storage capacitor (118).

[0089] If the anode of the second thyristor (114) is coupled to the negative terminal of the battery, the control circuit (124) can be configured to control the first switch (108) so that it is turned on during the short circuit detection phase and during pre-charging of the storage capacitor (118).

[0090] The control circuit (124) may be configured such that after precharging of the storage capacitor (118), the first and second switches (108, 110) are turned on and the first and second thyristors (112, 114) are turned off.

[0091] The third switch (120) may be a third thyristor, and the control circuit (124) may be configured to apply a control signal to a gate of the third thyristor.

[0092] During a phase of disconnecting the battery from the bus after precharging the storage capacitor (118), the control circuit (124) may be configured to turn on the third switch (120) after the first and second switches (108, 110) are turned off.

[0093] During the measurement of the voltage at the terminals of the storage capacitor (118) carried out during the short circuit detection phase, the control circuit (124) can be configured to switch off the second thyristor (114).

[0094] A vehicle battery control system (1000) can be summarized as including at least one short circuit detection device (100) according to the above-mentioned embodiments.

[0095] A power converter (2000) can be summarized as comprising at least one short circuit detection device (100) according to the above-mentioned embodiments.

[0096] The first thyristor and the second thyristor (112, 114) may be part of a commutation unit of a power converter (2000).

[0097] The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments according to the detailed description above. In general, in the appended claims, the terms used should not be interpreted as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be interpreted as including all possible embodiments and the full range of equivalent forms to which these claims are given. Therefore, the claims are not limited by this disclosure.

Claims

1. A short circuit detection device, comprising: A control circuit is coupled to the DC circuit, the DC circuit comprising: a voltage source having terminals; a bus bar including at least two conductive elements, each of the at least two conductive elements being coupled to any one of the terminals of a voltage source; a first thyristor and a second thyristor coupled to a voltage source and to a bus; and at least one capacitive element forming a storage capacitor, the storage capacitor comprising terminals and electrodes, each of the electrodes of the storage capacitor being coupled to any one of the at least two conductive elements of the busbar, The control circuit is configured to control the bias and operation mode of the first thyristor and the second thyristor so that: During a detection phase of the short circuit, the first thyristor is placed in an off state and the second thyristor is reverse biased and conducts a non-zero reverse current charging the storage capacitor, and If the voltage at the terminals of the storage capacitor is less than or equal to the short-circuit threshold, the first thyristor and the second thyristor are placed in the off state, or if the voltage at the terminals of the storage capacitor is higher than the short-circuit threshold, the first thyristor is placed in the on state and the second thyristor is placed in the off state to precharge the storage capacitor. 2 . The short circuit detection device according to claim 1 , wherein the short circuit threshold is equal to 0. 3 .

3. The short circuit detection device according to claim 1, wherein: The voltage source is a DC voltage source including a battery; The DC circuit includes a first switch and a second switch, the first switch coupling the positive terminal of the battery to a first conductive element of the at least two conductive elements of the bus bar, and the second switch coupling the negative terminal of the battery to a second conductive element of the at least two conductive elements of the bus bar; At least one of the first switch or the second switch is a relay; The DC circuit includes a discharge circuit of the storage capacitor, the discharge circuit includes a third switch, the third switch is coupled in series with the discharge resistor, and the discharge circuit is coupled in parallel with the storage capacitor; the first thyristor being part of a precharge circuit, the precharge circuit comprising a precharge resistor coupled in series with the first thyristor, the precharge circuit being coupled in parallel with one of the first switch or the second switch, the cathode of the first thyristor being coupled to a negative terminal of the battery or the anode of the first thyristor being coupled to a positive terminal of the battery; The second thyristor is coupled in parallel with one of the first switch or the second switch, an anode of the second thyristor is coupled to the negative terminal of the battery or a cathode of the second thyristor is coupled to the positive terminal of the battery.

4. The short circuit detection device according to claim 3, wherein: The control circuit is configured to apply a control signal to the gates of the first thyristor and the second thyristor, or The short circuit detection device includes a Zener diode and an RC circuit, wherein the anode of the Zener diode is coupled to the gate of the first thyristor, the cathode of the Zener diode is coupled to the anode of the second thyristor and to the first terminal of the RC circuit, and the second terminal of the RC circuit is coupled to the cathode of the first thyristor.

5. The short circuit detection device according to claim 3, wherein the control circuit is configured as: Prior to the detection phase, the first switch is closed and an initial measurement of the voltage at the terminals of the storage capacitor is made; If the initial measured value of the voltage is lower than or equal to the short-circuit threshold, the detection phase is initiated, or if the initial measured value of the voltage is higher than the short-circuit threshold, the storage capacitor is directly precharged.

6. The short circuit detection device according to claim 3, wherein: If the anode of the second thyristor is coupled to the negative terminal of the battery, the control circuit is configured to control the first switch such that the first switch is in a conducting state during the detection phase and during pre-charging of the storage capacitor. 7 . The short circuit detection device according to claim 3 , wherein the control circuit is configured to put the first switch and the second switch into an on state and put the first thyristor and the second thyristor into an off state after precharging of the storage capacitor. 8 . The short circuit detection device according to claim 3 , wherein the third switch is a third thyristor, and the control circuit is configured to apply the control signal to a gate of the third thyristor.

9. The short circuit detection device according to claim 3, wherein: During a phase in which the battery is disconnected from the bus bar after pre-charging of the storage capacitor, the control circuit is configured to turn on the third switch after the first switch and the second switch are turned off.

10. The short circuit detection device according to claim 3, wherein: During the measurement of the voltage at the terminals of the storage capacitor performed during the detection phase, the control circuit is configured to put the second thyristor into an off-state.

11. A system comprising: DC circuits, including: a voltage source having terminals; a bus bar including at least two conductive elements, each of the at least two conductive elements being coupled to any one of the terminals of a voltage source; a first thyristor and a second thyristor coupled to a voltage source and to a bus; and at least one capacitive element forming a storage capacitor, the storage capacitor comprising terminals and electrodes, each of the electrodes of the storage capacitor being coupled to any one of the at least two conductive elements of the busbar; and A short circuit detection device comprises a control circuit configured to control bias and operation mode of a first thyristor and a second thyristor so that: During a detection phase of the short circuit, the first thyristor is placed in an off state and the second thyristor is reverse biased and conducts a non-zero reverse current charging the storage capacitor, and If the voltage at the terminals of the storage capacitor is less than or equal to the short-circuit threshold, the first thyristor and the second thyristor are placed in the off state, or if the voltage at the terminals of the storage capacitor is higher than the short-circuit threshold, the first thyristor is placed in the on state and the second thyristor is placed in the off state to precharge the storage capacitor.

12. The system of claim 11, wherein: The voltage source is a DC voltage source including a battery; The DC circuit includes a first switch and a second switch, the first switch coupling the positive terminal of the battery to a first conductive element of the at least two conductive elements of the bus bar, and the second switch coupling the negative terminal of the battery to a second conductive element of the at least two conductive elements of the bus bar; At least one of the first switch or the second switch is a relay; The DC circuit includes a discharge circuit of the storage capacitor, the discharge circuit includes a third switch, the third switch is coupled in series with the discharge resistor, and the discharge circuit is coupled in parallel with the storage capacitor; the first thyristor being part of a precharge circuit, the precharge circuit comprising a precharge resistor coupled in series with the first thyristor, the precharge circuit being coupled in parallel with one of the first switch or the second switch, the cathode of the first thyristor being coupled to a negative terminal of the battery or the anode of the first thyristor being coupled to a positive terminal of the battery; The second thyristor is coupled in parallel with one of the first switch or the second switch, an anode of the second thyristor is coupled to the negative terminal of the battery or a cathode of the second thyristor is coupled to the positive terminal of the battery.

13. The system of claim 12, wherein: The control circuit is configured to apply a control signal to the gates of the first thyristor and the second thyristor, or The short circuit detection device includes a Zener diode and an RC circuit, wherein the anode of the Zener diode is coupled to the gate of the first thyristor, the cathode of the Zener diode is coupled to the anode of the second thyristor and to the first terminal of the RC circuit, and the second terminal of the RC circuit is coupled to the cathode of the first thyristor.

14. The system of claim 12, wherein the control circuit is configured to: Prior to the detection phase, the first switch is closed and an initial measurement of the voltage at the terminals of the storage capacitor is made; If the initial measured value of the voltage is lower than or equal to the short-circuit threshold, the detection phase is initiated, or if the initial measured value of the voltage is higher than the short-circuit threshold, the storage capacitor is directly precharged. 15 . The system of claim 12 , wherein the control circuit is configured to, after pre-charging of the storage capacitor, place the first switch and the second switch in an on state and place the first thyristor and the second thyristor in an off state.

16. The system of claim 12, wherein: During a phase in which the battery is disconnected from the bus bar after pre-charging of the storage capacitor, the control circuit is configured to turn on the third switch after the first switch and the second switch are turned off.

17. A power converter comprising: At least one short circuit detection device, comprising: A control circuit is coupled to the DC circuit, the DC circuit comprising: a voltage source having terminals; a bus bar including at least two conductive elements, each of the at least two conductive elements being coupled to any one of the terminals of a voltage source; a first thyristor and a second thyristor coupled to a voltage source and to a bus; and at least one capacitive element forming a storage capacitor, the storage capacitor comprising terminals and electrodes, each of the electrodes of the storage capacitor being coupled to any one of the at least two conductive elements of the busbar, The control circuit is configured to control the bias and operation mode of the first thyristor and the second thyristor so that: During a detection phase of the short circuit, the first thyristor is placed in an off state and the second thyristor is reverse biased and conducts a non-zero reverse current charging the storage capacitor, and If the voltage at the terminals of the storage capacitor is less than or equal to the short-circuit threshold, the first thyristor and the second thyristor are placed in the off state, or if the voltage at the terminals of the storage capacitor is higher than the short-circuit threshold, the first thyristor is placed in the on state and the second thyristor is placed in the off state to precharge the storage capacitor.

18. The power converter of claim 17, wherein the first thyristor and the second thyristor are part of a commutation unit of the power converter.

19. The power converter of claim 17, wherein: The voltage source is a DC voltage source including a battery; The DC circuit includes a first switch and a second switch, the first switch coupling the positive terminal of the battery to a first conductive element of the at least two conductive elements of the bus bar, and the second switch coupling the negative terminal of the battery to a second conductive element of the at least two conductive elements of the bus bar; At least one of the first switch or the second switch is a relay; The DC circuit includes a discharge circuit of the storage capacitor, the discharge circuit includes a third switch, the third switch is coupled in series with the discharge resistor, and the discharge circuit is coupled in parallel with the storage capacitor; the first thyristor being part of a precharge circuit, the precharge circuit comprising a precharge resistor coupled in series with the first thyristor, the precharge circuit being coupled in parallel with one of the first switch or the second switch, the cathode of the first thyristor being coupled to a negative terminal of the battery or the anode of the first thyristor being coupled to a positive terminal of the battery; The second thyristor is coupled in parallel with one of the first switch or the second switch, an anode of the second thyristor is coupled to the negative terminal of the battery or a cathode of the second thyristor is coupled to the positive terminal of the battery.

20. The power converter of claim 19, wherein: The control circuit is configured to apply a control signal to the gates of the first thyristor and the second thyristor, or The short circuit detection device includes a Zener diode and an RC circuit, wherein the anode of the Zener diode is coupled to the gate of the first thyristor, the cathode of the Zener diode is coupled to the anode of the second thyristor and to the first terminal of the RC circuit, and the second terminal of the RC circuit is coupled to the cathode of the first thyristor.

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